Sediment mobilization and seawater warming affect ecophysiology of the clam polititapes rhomboides

Poster.-- Poster.-- VIII International Symposium on Marine Science, Las Palmas de Gran Canaria, 6-8 July 2022High-energy hydrodynamic events associated to currents and waves may disturb bivalve mollusks´ ecophysiology, especially those buried in the the sea bed due to sediment mobilization. Evidences of massive mortality for the clam Polititapes rhomboides (banded carpet shell clam) in Galicia (NW Spain) have been associated to warm water temperatures and high wave magnitudes above climatic averages and the presence of rickettsias (intracellular prokaryotic colonies) in gills (Villalba et al. 1999; Darriba et al. 2019; Villacieros-Robineau et al. 2021)Project PID2019-106008RB-C21 financed by MCIN/AEI/10.13039/501100011033N

Immune and physiological responses of clams (Polititapes rhomboides) under sediment mobilization and seawater warming conditions

Poster.-- 4th Congress of the International Society of Fish & Shellfish Immunology, December 12-15, 2022, Bode, NorwayHigh-energy hydrodynamic events associated with currents and waves may disturb bivalve mollusks' ecophysiology, especially those buried in the sea bed where the bottom boundary layer dynamics may mobilize and resuspend the surface sediments. Evidence of massive mortality for the clam Polititapes rhomboides (banded carpet shell clam) in 2010 in Galicia (NW Spain) has been associated to warm water temperatures and high wave magnitudes above climatic averages and the presence of rickettsias (intracellular prokaryotic colonies) in gills. To monitor in the laboratory the environmental conditions observed in 2010, clams were subjected to intense sediment mobilization (four cycles of sediment remobilization, each followed by a calm period) and seawater warming (from 15°C to 18°C). Immune system, behavioral, and ecophysiological clams' responses were then evaluated. Nitric oxide (NO) production increased synergistically with seawater warming and sediment remobilization. Taking into account the four cycles of sediment remobilization, clams responded by increasing NO production as early as the first cycle in what we could call an acute effect. However, the most striking effect was the increased NO response after a second stimulation (the following sediment remobilization cycles), suggesting that clams achieve a kind of alertness the first time they are exposed to a stimulus through a mechanism possibly related to "trained immunity". Seawater warming and sediment mobilization presented also synergistic effects causing the lowest valve opening amplitude. Besides, sediment remobilization caused abrupt decrease in clearance rates of clams suggesting that reduced valve opening during this stage may have altered filtration processes of phytoplankton uptake. Metabolic rate as oxygen consumption showed a synergistic increase with both abiotic stressors. Considering the NO response and the ecophysiology data we could suggest that clams respond to stress increasing metabolism to obtain energy (ATP) and oxygen consumption by aerobic respiration. ATP production involves the generation of reactive oxygen species (ROS) including NO as by-products. The anti-oxidant system can balance the ROS production but this could be drastically altered (disruption of cytoskeleton and apoptotic cell death) if ROS production is greater and faster than the antioxidant system can regulate, which seems not to be the case for this particular experimentProject PID2019-106008RB-C21 financed by MCIN/AEl/10.13039/501100011033N

Catalogue of parasites and diseases of the common cockle Cerastoderma edule

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Inventario de parasitos e enfermidades do berberecho Cerastoderma edule

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Atlas des parasites et maladies de la coque commune Cerastoderma edule

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Catálogo de parasitas e patologias do berbigão-vulgar Cerastoderma edule

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Geographical variation in shell shape of the pod razor shell Ensis siliqua (Bivalvia: Pharidae)

The present study assessed the existence of variation in the shell shape of the pod razor shell (Ensis siliqua) throughout its distributional range in the north- eastern Atlantic. Shells of E. siliqua caught at seven collecting sites (three in Portugal, three in Spain and one in Ireland) were studied by geometric morphometric methods, using both landmark- and contour-based methods. Both approaches (landmarks inside the valves and shell outline) discriminated the shells from Aveiro (centre of Portugal) and Strangford Lough (Ireland) from those caught in the nearby localities (remaining Portuguese and Spanish sites,maximum distance of 550 km by sea). Landmark analysis revealed that shells from Aveiro were more similar to shells from Ireland (*1,500 km far away). Contour anal- ysis revealed that shells from Aveiro had a shape with a comparatively larger height-to-width ratio, whereas shells from Ireland showed a slightly more curved outline than in the remaining sites. Landmark- and contour-based methods provided coherent complementary information, confirming the usefulness of geometric morphometric analyses for discerning differences in shell shape among populations of E. siliqua. A brief review of previous applications of geometric morphometric methods to modern bivalve spe- cies is also provided.The authors would like to thank Dr. Dai Roberts and Adele Cromie for providing samples of pod razor shells from Ireland. This study was funded by Community Initiative Programmes (INTERREG-IIIB, Atlantic Area) Sustainable HARvesting of Ensis (090–SHARE) and Towards Integrated Management of Ensis Stocks (206–TIMES) from the European Community. Marta M. Rufino and Paulo Vasconcelos benefited from postdoctoral grants (SFRH/BPD/14935/2004 and SFRH/BPD/26348/2006, respectively) awarded by the Fundação para a Ciência e Tecnologia (FCT—Portugal). Finally, the authors acknowledge three anonymous referees for valuable comments and suggestions that greatly improved the revised manuscript.publishe

Lead accumulation in extracellular granules detected in the kidney of the bivalve

Populations of the marine molluscan bivalve Dosinia exoleta in Galicia (northwest Spain) present lead (Pb) concentrations above the limit for human consumption. Accordingly, its collection for human consumption was forbidden since 2008. The high bioaccumulation of Pb in this species is surprising given that Pb concentrations are not very high in its environment and that other bivalve infaunal species inhabiting the same areas do not show such high Pb contents. This study reports the discovery and description of extracellular granules present in the kidney tubule lumina of this species. Large granules (20−200 μm) mainly composed of calcium phosphate represent between 50% and 75% of the dry weight of the kidneys. Metal analysis revealed that from 78 to 98% of the Pb body burden was present in the kidney, and from 87% to 92% of this Pb within the kidney was contained in metal rich granules. Most of the zinc in these bivalves was also found to be associated with these kidney granules, while other metals, such as copper and cadmium, were associated with other kidney fractions. This study confirms that the high Pb concentrations observed in D. exoleta, and the relationship of Pb concentration with individual size, are due to the inclusion of Pb in kidney granules that accumulate in the kidney lumen over the course of the bivalve’s life

Taphonomy and dissolution rates of the razor clam Ensis magnus shells: Current status and projected acidification scenarios

14 pages, 8 figures, 4 tables.-- Under a Creative Commons licenseThe analysis of the natural variability of seawater (Ta, Ωaragonite and pCO2) at Rodas Beach (NW Iberian Peninsula, Spain) revealed an increase of acidification. However, such pH change was not linked to any detrimental effect of the shell taphonomic characteristics of live razor clams harvested during distinct temporal series (length, thickness, organic content or strength). Temperature affected negatively shell strength and thickness, although the large correlation between the environmental variables would limit the individual characterization. Modelled trends in pH (and Ωaragonite) showed a significant decrease in the last 20 years, despite Ω > 1. Therefore, more recent shells are being secreted in a progressively less saturated carbonate environment and, consequently, more prone to suffer dissolution (and weakening) in projected climatic scenarios. When shells of harvested razor clams were exposed to projected climatic scenarios in the laboratory, dissolution rates were significantly greater for cold-acidic scenarios (more corrosive) as compared to warm-acidic. The median dissolution time (DT50) for shells under the cold-acidic scenario was reduced by half (15 years) when compared to the values observed for shells under current water chemistry conditions (30 years). Galician coastline, often characterised by pCO2-rich and cold waters due to upwelling system, would represent the most corrosive scenario for the shells according to the responses monitored in our survey which highlight future compromise for the ecosystem services supplied by these hard skeletons. Future climate scenarios might condition performance of bivalves but also more complex processes related to carbonate structures. Local biodiversity may be lowered which may reduce the possibility that many species find shelter and feeding grounds, diminishing the optimal substrate for other organisms as needed elements for optimal services in the ecosystemsJMFB acknowledges the project ARIOS (CTM2016-76146-C3-2-R/CTM2016-76146-C3-1-R) funded by the Spanish government through the Ministerio de Economía y Competitividad that included European FEDER funds and the project Atlazul (0755_ATLAZUL_6_E) co-financed by the Interreg-POCTEP Programme through the European Regional Development Fund. AV and FFP were supported by BOCATS2 (PID2019-104279 GB-C21) project funded by MCIN/AEI/10.13039/501100011033 and contributing to 628 WATER:iOS CSIC PTI. LGP was supported by a Talento Senior Grant (16_IN585A_2020_986937) from Xunta de Galicia (Spain)Peer reviewe

Understanding the mortality event of Polititapes rhomboides in 2010 in Galicia

Poster.-- 19th International Conference on Diseases of Fish and Shellfish, Porto, Portugal, 09 - 12 September, 2019A mortality event of Polititapes rhomboides, occurred in June 2010, in subtidal natural beds in Ria of Vigo. It was asociated with a very high infection of prokaryotic intracelular colonies in gills.Peer reviewe